which planet you want next ?

I never want to see Gungans in this game even if i get to crush them. They are the most annoying creation ever in the history of everything and if they become a playable race this game would be over in 2 seconds.

Because the foundation of the two types of games are markedly different. Those difference are part of every aspect of a title. Besides, even if it were possible, the establishment of niche areas in a game is never successful. We've already seen that in SWTOR.
A sense of nostalgia is exactly what you're looking for. If your intent were truly as simply as you claim, then you be willing to advocate any number of systems that would compliment the existing game without requiring a massive redesign of the game's foundation.

Yavin 4
Kashyyk
Myygeto
Kamino

No idea what this is; are you sure your spelling is correct?

Yavin. Its another iconic world though I wonder if a little boring.

Zeltros, Mutanda, Bothawui, Ossus ( though it would be in bad shape still ) , Hapes, Tannab, Mannan and or Mon cal

So what is your definition of successful? I take it you don't take part in space combat? I don't either, but I have guildies who do and enjoy it. So should they take it away and label it as a niche feature? If they added an area where people can partake in X sandbox activity, how would that hurt as long as it doesn't interfere with the story/questing part of the game? I don't see people leaving because of a feature like this being added. I see people subscribing.

It has nothing to do with the "foundation" of the game. The foundation is Star Wars. The Old Republic was programmed with the Hero Engine, which is HIGHLY customizable and with some effort, the areas can be built upon and made quite expansive.

Try thinking out of the box and imagine a game that can appeal to fans of several types of MMO's.

Oh, and you don't know me lol so try not to presume that I yearn for nostalgia. I have a Nintendo. If I wanted to feel nostalgic, I'd play Super Mario Brothers.

Mygeeto

I'd love to see a 'new' world and by that I mean - not previously mentioned in the prequels, or original trilogy, or EU.

I was very happy with Voss, it was infact, one of my favourite planets - I enjoyed the story a great deal.

I'd love to see what the design team could come up with, given a blank canvas again.

That said, if it had to be established, I'd like to see Mon Cal or perhaps Yavin Four, I'd like to be more inventive with my suggestions, but Yavin is very iconic, and Mon Cal would offer alot of pontential for new and interesting slants on traditional landscapes, given the aquatic nature of the inhabitants and environs.

I enjoy it, actually, and others do as well. That hardly makes it successful, and also means it is a waste of resources to continue supporting it. That's why they're actively working toward a redesign.
Then you don't understand market economics as it relates to the service industry. To add something in, they have to provide continued support for it. If that element only appeals to a fraction of the community, they can only devote a fraction of their resources to its continued development. As such, they cannot support it properly, which in turn becomes a black mark for the game as a whole. They are then left with the choice of devoting additional resources to said niche feature in an attempt to quell general consumer unrest, thereby sacrificing support in other, more utilized areas of the game, or stick with the way things are and let the game be labelled a failure. It's a very real downward spiral that once begun is almost impossible to halt.

That's what you're recommending for SWTOR. This is not a sandbox game. It is incapable of being a sandbox game. We've known that for years now. Accept it or get lost; we don't need sandbox elements forcing SWTOR into an early grave, like they did SWG.
No, the foundation is the game coding and infrastructure. The Hero System is highly customizable; it was customized to support the current game. Not a sandbox title.
Sandbox games do exactly the opposite. Then lessen the appeal of a game tothe general population. The sooner you realize that, the sooner you can begin moving forward.